He needs to show Argentine fans he's the world's greatest soccer player when wearing the country's famous blue-and-white shirt.

Messi starts romancing the crowds when Argentina opens the 3 1/2-week Copa America - the South American championship - against Bolivia on Friday.

Messi has rarely played with the same allure for Argentina as he has for Barcelona - and never when it counts. Argentina exited last year's World Cup with a humiliating 4-0 loss in the quarterfinals to Germany. Messi didn't score during the entire tournament.

Everything is now set for Messi to excel. An elite power without much recent success, Argentina is the host. Messi is coming off his greatest season at Barcelona, and new coach Sergio Batista has his players trying to mimic the Catalan team's style of quick passes and possession play.

"Messi is going to have a great Copa America," Batista said. "Having the best player in the world means a lot, and we'll try to make him comfortable so he produces his best. This is an enormous advantage."

Messi is an outsider at home. He left Argentina for Barcelona as a youth player, spent his formative years in Spain and has never played for one of his country's famed clubs.

His personality also leaves many Argentines cold. He seldom jokes around, seems uncomfortable speaking and lacks the charisma of Diego Maradona. Known in Spanish as "La Pulga" (The Flea), Messi has yet to lift a trophy for his country of birth.

"It's been awhile since Argentina has won an important title," Messi said. "We need some joy for ourselves and our fans."

Carlos Tevez is likely to be the other main scoring threat for Argentina. Known affectionately as "Carlitos," he's the country's most popular player and is the opposite of Messi. Tevez starred for Boca Juniors, grew up poor in a Buenos Aires shantytown and never stops smiling.

Argentina's last major international title was in 1993, the Copa America. The last of its two World Cup titles was in 1986, and its club scene is a mess.

River Plate, which has won more league titles than anyone, was relegated to the second division last week, sparking riots between hooligans and 2,200 police. The area around River Plate's Monumental Stadium - where the Copa America final will be played July 24 - turned into a smoldering war zone and was closed for several days while a prosecutor opened an investigation.

The club said this week it has begun making repairs after hooligans ransacked concession areas, ripped out seats and smashed fixtures in toilets.

"The way the stadium was left was shocking," prosecutor Gustavo Galante said.

Security officials say 2,000 police have been assigned to Friday's opening match between Argentina and Bolivia.

On the field, Brazil is still Argentina's biggest worry.

The Brazilians have defeated Argentina in the past two Copa America finals, and have won four of the last five titles. Argentina is a slight favorite this time, adding even more pressure.

Brazil, which was also knocked out of the World Cup in the quarterfinals, is missing Kaka, Luis Fabiano, Ronaldinho and Adriano. This team is rebuilding and will be led by youngsters such as Neymar, Alexandre Pato, Lucas and Paulo Henrique Ganso.

Argentina and Brazil seem certain to advance from the group stage, and the real action will start in the quarterfinals of July 16 and 17.

Uruguay, Chile, Paraguay and Colombia are considered long shots, with Ecuador, Bolivia, Peru and Venezuela given little chance.

Also included are Mexico and Costa Rica, which are playing as invited teams to increase the field to 12. Both have arrived with youth teams instead of the senior sides that played in the recent Gold Cup.

Mexico defeated the United States 4-2 in that final of that regional championship. Eight players from the Copa America squad were suspended Tuesday for breaking training rules.

Costa Rica replaced Japan, which withdrew after the March 11 earthquake and tsunami.